A 7.0-magnitude quake struck off the northeast of Papua New Guinea on Tuesday, the US Geological Survey said, but there was no tsunami warning issued.

The quake hit at 5:13 pm (0713 GMT) 141 kilometres (88 miles) north of the country's second largest city of Lae and 443 kilometres from the capital Port Moresby at a depth of 201 kilometres, it said.

"A destructive tsunami was not generated based on earthquake and historical tsunami data," the Pacific Tsunami Warning Center said in a statement.

Geoscience Australia measured the quake at 6.8 magnitude and at a depth of 215 kilometres but agreed it was unlikely to generate dangerous waves in the developing Pacific island nation.

"It's pretty deep so it's not a tsunami threat we believe, even though it's slightly offshore," Geoscience Australia seismologist Clive Collins told AFP.

Collins said there had been reports of the quake being felt as far away as Goroko, a highland region about 250 kilometres from the epicentre.

"There would be quite some shaking to the areas close by... because it's about 20 kilometres offshore," Collins said.

"So it's obviously been felt in a wide area around Papua New Guinea, which you would expect from something that big."

Quakes of such magnitude are common in impoverished PNG, which sits on the so-called "Pacific Ring of Fire", a hotspot for seismic activity due to friction between tectonic plates.

"That northern part of Papua New Guinea is subject to quite strong earthquakes reasonably frequently," Collins said, adding that the biggest risk in the mountainous country was generally from landslips caused by tremors.

"There are very steep valleys and if it's been wet you get landslides which generally cause trouble. But I think this being a little bit offshore it may not be such a problem," he said.

"Of course it will be a while before we know that."

A giant tsunami in 1998 killed more than 2,000 people near Aitape, on the country's northwest coast.